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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include "qpio.h"
# QPIO_RBUCKET -- Load the bucket containing the specified event into the
# QPIO descriptor, returning EOF if the numbered event does not exist.
int procedure qpio_rbucket (io, evi)
pointer io #I QPIO descriptor
int evi #I bucket number desired
int ev1, ev2, nb
int offset, bkno, status
begin
# Event does not exist?
if (evi < 1 || evi > IO_NEVENTS(io))
return (EOF)
# Bucket already loaded?
bkno = EVI_TO_BUCKET(io,evi)
if (bkno == IO_BKNO(io))
return (bkno)
# Determine range of events in bucket.
ev1 = BUCKET_TO_EVI(io,bkno)
ev2 = min (IO_NEVENTS(io), ev1 + IO_BUCKETLEN(io) - 1)
# Physically read the bucket.
nb = IO_SZBBUCKET(io)
offset = (bkno - 1) * nb + IO_FBOFF(io)
call fm_lfaread (IO_CHAN(io), Mems[IO_BP(io)], nb, offset)
call fm_lfawait (IO_CHAN(io), status)
if (status < nb)
return (EOF)
# Update the bucket descriptor.
IO_BKNO(io) = bkno
IO_BKFIRSTEV(io) = ev1
IO_BKLASTEV(io) = ev2
return (bkno)
end
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